As described in Patent Document 1, there is a well-known device interposed in an exhaust-gas flow path, which device recovers exhaust gas heat by performing heat exchange between the exhaust gas from an internal combustion engine and a heat exchange medium, such as cooling water of the internal combustion engine and the like. In this device, a tube stacked body is composed by stacking a plurality of flattened tubes having a circular torus shape, an exhaust pipe is inserted into the tube stacked body, and a cylindrical case is disposed on an outside of the tube stacked body. Further, in this device, there is provided, in the exhaust pipe, a shutoff valve that shuts off the exhaust gas flowing out from the exhaust pipe. When the internal combustion engine is being warmed up, the shutoff valve is closed. According to such configuration, the exhaust gas is led into a space between the cylindrical case and the tube stacked body during warming-up, and then, led into a space between the flattened tubes, and delivered to an opposite space between the cylindrical case and the tube stacked body. After that, the exhaust gas is discharged downstream of the exhaust-gas flow path from the opposite space between the cylindrical case and the tube stacked body. Further, the flow paths formed inside of the respective flattened tubes are connected in parallel to each other, and by flowing the heat exchange medium through the connected flow paths, heat exchange is performed between the exhaust gas and the heat exchange medium.